Pressure roller in a sanding device

ABSTRACT

IN A SANDING DEVICE EMPLOYING A SANDING BELT OF COMPARATIVELY WIDE WIDTH, A PRESSURE ROLLER IS LOCATED IN A FACE TO FACE POSITION WITH THE MATERIAL TO BE PROCESSED AND HAS AN AIR TUBE EXTENDING IN THE LONGITUDINAL DIRECTION OF THE STATIONARY SHAFT OF THE PRESSURE ROLLER A PLURALITY OF RINGS MOUNTED CIRCUMFERENTIALLY THEREOF, AND THE PRESSURE APPLIED TO THE MATERIAL TO BE PROCESSED IS CONTROLLABLE BY ADJUSTING AIR PRESSURE INSIDE SAID AIR TUBE.

J 9 KATSUJI HAsEGAwA 3,553,399

PRESSURE ROLLER IN A SANDING DEVICE Filed Sept. 5, 1968 INVEN'JUR. a" Wa- Md a United States Patent PRESSURE ROLLER IN A SANDING DEVICE Katsuji Hasegawa, Nagoya, Japan, assignor to Kabushiki Kaisha Meinan Seisakusho, Nagoya, Japan Filed Sept. 3, 1968, Ser. No. 756,984 Claims priority, application Japan, Sept. 4, 1967, 42/ 56,668

Int. Cl. B24b 21/12 US. Cl. 51-141 3 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a pressure roller in a sanding device.

In the conventional pressure roller of this type assembled with plural rings passed by spring means, such disadvantages are encountered as that the outer peripheries of the assembled rings are irregular, and error in pressure control is very often caused from even a slight distortion of the springs. Another type of pressure member assembled with plural plate pieces has the further disadvantages that frictional resistance is larger between surfaces of assembled plate pieces and a board to be processed as to damage the board surface and fail to make a smooth transfer of the board, which results in high abrasion of the plate pieces.

The principal object of the present invention is to provide a pressure roller in a wide belt sander located in face to face position with the material to be processed and having an air tube provided of the stationary shaft of the pressure roller; and plural rings provided circumferentially thereon; and characterized in that pressure application is controllable with adjustment of pressure inside the air tube.

In the accompanying drawings:

FIG. 1 is a front view of a preferred embodiment of a pressure roller made according to the present invention;

FIG. 2 is a cross sectional view of the same along the line II-II of FIG. 1;

FIGS. 3 and 4 are illustrations of wide belt sanders, to each of which a pressure roller of the present invention is attached;

FIG. 5 is a perspective view of a pressure roller of the conventional type; and

FIG. 6 is a perspective view of another type of pressure member.

In FIGS. 1 and 2, numeral 1 is a stationary shaft, around which there are provided fixed stays or stops for bearings 5- andS, an air tube 7 and a key 6 for regulating a position of bearings. Said air tube 7 is received within the groove 2 provided at one portion of the said shaft. Said kev 6 is fitted into a groove 3 provided at the diametrically opposite portion of the stationary shaft from the air tube 7. Mounted around these attachments to the shaft 1 are plural ball bearings 4, 4 and 4", which are in a side by side arrangement to form the outer periphery of a pressure roll P. In some cases, a packing -8 of a plastic material, for example Teflon (tetrafluoroethylone), may be inserted adjacent ball bearings to provide a smooth pressing motion of the ball bearings and serve for 3,553,899 Patented Jan. 12, 1971 a dust protector for the pressure roll P. A more complete dust protection of the pressure roll P may be achieved by a rubber film, for example in a tubular form, covering the outer rings of the bearings.

The thus constructed pressure roll P may be mounted in a known type of wide belt sander to cooperate either with a contact roller C or a base B so that the outer rings of the ball bearings 4, 4' and 4" and the roller C contact opposite faces of the material to be processed M such as a board. The wide belt sander in FIG. 3 adopts a contact roller system and that in FIG. 4 employs a platen system. In these drawings, I indicates an idle roller, R indicates a feed roller, and S indicates a sanding belt. When the material to be processed M is fed between the contact roller C or the base B and the pressure roller P, the ball bearings rotate to press the air tube '7, through which compressed air pressure is applied to the material to be processed M. The outer rings of the ball bearing assembly rotate with the material to be processed M and contribute to make a smooth face on the material to be processed M without damage thereto, and assure a steady transfer or feed of the material M, without frictional resistance between the bearings and the material. Pressure which is applied to the material to be processed is easily adjustable by controlling pressure the supply to the air tube 7 to provide for an effective grinding condition depending upon the material to be processed. The respective ball bearings are movable to press the air tube according to the surface condition of a material to be processed, which assures a steady pressure control, thereby performing an eflicient grinding. The key 6 which functions to regulate the position of the bearings serves to maintain the outer peripheries of respective bearings in a regular position in relation to a material to be processed, even when they are not in operation. This eliminates irregularity of the outer peripheries of respective rings, which is encountered in the conventional pressure roll. Disassembly or assembly of the pressure roll is conducted easily by letting air out of the tube.

For better understanding of the features of the present invention, two examples of the conventional pressure members will be described. One example is a roller type of pressure member, as shown in FIG. 5, in which plural rings 12, each having cavities 13, are assembled around a shaft 15, which is provided with equi-spaced plural radical grooves 16. The grooves 16 and cavities 13 are registered with each other to accommodate springs 14. The pressure roller of this type has such disadvantages as irregularity in the outer periphery of the assembled rings and instability in pressure control caused from even slight distortion of the springs. Another type of conventional pressure member as shown in FIG. 6 has a fiat contact face, formed by plate pieces 10 mounted on a resilient material 11 accommodated within a holder 9 and fitted to both edges of the holder. This type of pressure member is larger in frictional resistance due to its flat face, when contacted with the material to be processed. This results disadvantageously in damage of the processed material face and high abrasion of the plate pieces.

The pressure roll in the present invention, of which the pressure application system is constructed from an air tube and a ball bearing assembly, overcomes the disadvantages of the conventional pressure roll and provides many advantages, so that it is most useful as a pressure applying means for woodworking, especially it provides an excellent performance as a pressure applying means in a wide belt sander, and improves the grinding technique.

Thus, the pressure roll of the present invention gives a great contribution to the relevant industrial field as an efficient and simple pressure device.

I claim:

1. Ina sander having a sanding belt disposed to engage one surface of a workpiece:

a pressure roller disposed to engage the opposite face of the workpiece and hold the workpiece in engagement with the belt,

said pressure roller comprising:

a stationary shaft, a plurality of rings surrounding said shaft coaxially thereof, and an air tube disposed between said rings and said shaft to engage the insides of said rings and to urge said rings resiliently into engagement with the workpiece, said tube being adapted to be filled with compressed air and to yield when the pressure 4 exerted by the workpiece 0n the rings exceeds the pressure of the air within the tube.

2. A sander as claimed in claim 1, wherein said air tube is disposed within a groove in the periphery of said shaft extending longitudinally of the shaft.

3. A sander as claimed in claim 2, wherein the rings form the outer races of ball bearings whose inner races engage said tube.

References Cited OTHELL M. SIMPSON, Primary Examiner 

